It is often useful, in a timepiece mechanism, to be able to control the same pivoting wheel set in such a way as to obtain a different response depending on the pivoting direction applied. Such a function is generally performed by a differential mechanism, which can be bulky and costly, especially if the wheel set includes several entries.
EP Patent Application No 1429213 A2 in the name of FRANK MULLER WATCHLAND describes a unidirectional wheel with curved or inclined paddles like blades, working in buckling.
EP Patent No 1738229B1 in the name of MECO describes a hollow crown including a first elastically deformable element cooperating in a first rotational direction with a rigid element, whilst the rotational torque transmitted by one of these elements to the other is lower than a predetermined value above which the first deformable element is susceptible to be deformed and to cease its cooperation with this rigid element. A pipe is positioned in the crown housing and includes means for fixing a winding stem. The first deformable element is integral with this pipe regardless of the rotational torque value, and the rigid element is fixed with respect to the crown. The first deformable element cooperates in rotation with the internal edge of the rigid element which is annular in shape.
EP Patent No 1843225B1 in the name of ETA describes a one way reverser mechanism with an elastic coupling device capable, with at least one locking arm, of coupling or uncoupling the two wheels of a wheel set with two coaxial wheels, according to the direction of rotation of the motor pinion, at least one of these locking arms being able to cooperate with a cup on the inner periphery of the driven wheel.
CH Patent No 702 924 B1 in the name of PATEK PHILIPPE takes up the same principle, and describes a pinion and a wheel mounted coaxially, with a single elastic return means that cooperates, in certain discontinuous positions, solely between, on the one hand, a driving part integral with the pinion, and on the other hand, a female wolf-tooth toothing that includes a second drive part integral with the wheel. This elastic return means includes elastic clicks that are not continually in contact with this second drive part.